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Waves

Waveform

Obtained by plotting instantaneous values of a time-varying quantity against time.

Periodic Waveform

A pattern repeats after time. Periodic time is and frequency is .

Alternating Waveform

A waveform that changes in magnitude and direction with time. Is also a periodic waveform.

Symmetric Waveform

A periodic waveform that is symmetric about the time axis.

Sinusoidal Waves

An alternating and symmetric waveform. Same as vs (in rad). Also called sine waves or sinusoid.

When is:

  • - the wave is said to be leading by
  • - the wave is the reference
  • - the wave is said to be lagging by

Sinusoidal voltages can be easily generated using rotating machines.

Complex Waveforms

Periodic non-sinusoidal waveforms can be split into its fundamental and harmonics.

Fundamental Waveform

Harmonics

Sine waves with higher frequencies which is a multiple of .

Harmonics are grouped into:

  • odd harmonic when is odd.
  • even harmonic when is even.